Last week's episode of Supernatural had the Winchester boys once again pitted against their arch nemesis, Bela. Despite their crack detective skills, they were never able to determine Bela's actual identity, but retired hunter Rufus Turner was more successful. He informs the quiptastic Dean that while Bela burned off her fingerprints, he was able to identify Bela through her ear print, a technique which is big in England. And you know what? The show's done its research. Like low copy number DNA, ear print evidence appears to be something that is widely accepted in the U.K. but which courts on this side of the pond have determined is inadmissible. As an article in the Journal of Forensic Sciences notes, the use of ear prints or "earmarks" as evidence in criminal trials in the U.K. is expanding, despite a dearth of peer-reviewed scientific publications supporting their reliability.

Meanwhile, courts in the U.S. have rejected ear print evidence, with the essential case being State v. Kunze, 988 P.2d 977 (Wash.App. Div. 2 1999). In Kunze, David Wayne Kuze appealed his convictions for aggravated murder and other crimes, which were based upon the following facts:

An intruder entered the Washington home of James McCann; the intruder bludgeoned McCann in his head, causing his death and bludgeoned McCann's son Tyler in the head, causing a fractured skull. Tyler later told the police that he had been afraid to look at his attacker closely but that he thought that the intruder was a darkly complected male, possibly Puerto Rican, 25 to 30 years of age, who was wearing gloves but not glasses. Kunze was in his mid-forties, wore glasses, and had reddish-blond hair.

George Millar, a fingerprint technician with the Washington State Crime Laboratory, processed McCann's home for evidence and discovered a partial latent earprint on the hallway-side surface of McCann's bedroom door. He "dusted" the print by applying black fingerprint powder with a fiberglass brush and "lifted" the print by applying palm-print tape first to the door and then to a palm-print card. The resulting print showed the antitragus and portions of the tragus, helix, helix rim, and antihelix.

Notwithstanding Tyler's description of the intruder, the police were immediately interested in Kunze, because Kunze had been married to Diana James from 1976 to April 1994, and on December 12, 1994, four days before the intruder entered McCann's home, James told Kunze that she and McCann were planning to be married, which upset Kunze. The police interviewed Kunze several times and searched his belongings, but the searches did not disclose anything significant.

Meanwhile, Michael Grubb, a criminologist with the Washington State Crime Laboratory, compared the latent print from McCann's bedroom door with photos of the left side of Kunze's face and concluded that the latent print "could have been made by Dave Kunze." He also thought that "[i]t may be possible to obtain additional information by comparing the [latent print] to exemplar impressions." Millar and Grubb later met with Kunze to obtain earprint exemplars. For each of the seven exemplars they took, they had Kunze put hand lotion on his ear and press the ear against a glass surface with a different degree of pressure. They then dusted the glass with fingerprint powder and used palm-print tape to transfer the resulting impression onto a transparent plastic overlay. Based upon this process, Grubb concluded that "David Kunze is a likely source for the earprint and cheekprint which were lifted from the outside of the bedroom door at the homicide scene."

The trial court then held a Frye hearing to determine whether such ear print evidence was generally accepted in the relevant scientific community (forensic science), making it admissible expert evidence. At the hearing, numerous forensic scientists presented testimony about ear print evidence (their testimony is summarized in the opinion), which led the trial court to determine that it was generally accepted and thus admissible. After Kunze was convicted, he appealed, and the Court of Appeals of Washington agreed with him.

It found that 12 out of the 14 forensic scientists who testified at the Frye hearing "stated or implied that latent earprint identification is not generally accepted in the forensic science community." The only two dissenters were Grubb and Dutch policeman named Cor Van der Lug, whom the court found did not even explicitly say that ear print evidence was generally accepted in the forensic science community. The appellate court thus found the ear print evidence inadmissible, and I have not been able to find a subsequent U.S. case where such evidence has been deemed admissible.

It's important to note that while U.S. courts thus don't allow such latent ear print testimony, other evidence about ear prints. As the appellate court noted,

"Nothing in our holding bars testimony at retrial concerning visible similarities and differences between the latent print and the exemplars. This type of comparison-an 'eyeballing' of readily discernable similarities and differences-is based on 'visual techniques' that 'present jury questions,' or, in alternative terms, on personal knowledge that can readily be understood and evaluated by the jury. Thus, it need not be supported by a showing of general acceptance."